CLATHRODICTYON VESICULOSUM. 147 



internal structure cannot be satisfactorily studied in thin sections. In spite of 

 these drawbacks, I think there is no reason to doubt that the present form is a 

 perfectly distinct species. In its general structure it does not differ essentially 

 from A. clathratum, Nich., but it is at once separated from this, as from all other 

 recorded species of the genus Actinostroma, by the remarkable thickness of the 

 radial pillars and the general coarseness of the skeletal framework. Its general 

 aspect is exceedingly similar to that of the form described by Dr. Maurer from the 

 Devonian Rocks of Giessen, under the name of Stromatopora turgidecolumnata 

 ('Fauna der Kalke von Waldgirmes,' p. 112, Taf. iii, fig. 4). Dr. Maurer was,, 

 however, good enough to send me a minute fragment of this species, and so far as 

 I can judge from this— which is unfortunately in a very bad state of preservation 

 — I am disposed to think it is a true Stromatopora, with a porous skeleton-fibre, 

 allied to, or identical with, Stromatopora Beuthii, Barg. In the meanwhile, there- 

 fore, I have thought it safest to describe the present species — which is unquestion- 

 ably referable to the genus Actinostroma — as distinct. 



Distribution. — Rare in the pebbles of Devonian Limestone in the Triassic 

 Conglomerates of Teignmouth. 



Genus 2. — Clatheodictyon, Nicholson and Murie, 1878. 

 (Introduction, p. 77.) 



9. Clatheodictyon vesiculosum, Nich. and Mur. PI. XVII, figs. 10 — 13, and Pl- 



XVIII, fig. 12. 



? Stromatopora striatella, M'Coy. Brit. Pal. Foss., p. 12, 1851. (Non Stroma- 

 topora striatella, D'Orb.) 

 Clathrodictton vesiculosum, Nich. and Mur. Journ. Linn. Soc. Zool., vol. 



xiv, p. 220, pi. ii, figs. 11—13, 1878. 

 — — Nich. and B. Eth.,jun. Mon. Sil. Foss. Girvan, 



p. 238, pi. xix, fig. 2, 1880. 

 Stromatopora minuta, Rominger. Proc. Acad. Nat. Sci. Phil., p. 49, 1886. 

 Clathrodictton vesiculosum, Nich. Ann. Nat. Hist., ser. 5, vol. xix, p. 1, pi. 



i, figs. 1-3, 1887. 



The c<enosteum in this species is in the form of a laminar expansion, having 

 the lower surface covered with a concentrically striated or wrinkled epitheca 

 (Plate XVIII, fig. 12), and attached at one point to some foreign body. Adult 

 specimens grow to a size of half a foot or more in diameter, with a thickness in 



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